Research On The Key Methods For Route Travel Time Estimation System Based On GPS Floating Car

Since traffic conditions in urban is worse and worse day after day, the request of getting traffic support information while traveling is increasing and much more urgent. At the same time, more attentions have been paid to how to get timely, reliable and comprehensive traffic information. So service quality of advanced traveler information system ATIS is the point at issue. In the modern urban area, we always meet heavy congestion traffic with complex network of roads. So even the travelers with long-term experience driving or who will drive for business or tourism cannot deal with varying traffic state when driving in unfamiliar areas. In this situation, ATIS became the key to solve the problem whether the driver can get the traffic information with high quality and veracity.The thesis is based on the worse and worse traffic situation in modern urban, and the drivers are eager to get the information for traveling. By considering GPS floating car’s advantage of collecting traffic information while driving, the technology of how to make a great quantity of GPS information integrated, shared will be written in this thesis. And through a series of processing, the information about exited path and travel time will be mined. Then we can estimate the efficient travel route and travel time information for any OD. In this paper, the following works have been done already:Study on the framework of route travel time estimation system based on GPS floating car (FC-RTTES). On the basic of the system services objects and services content, the system analyzes the functional requirements of FC-RTTES. From the perspective of Application Development and algorithms, based on the software engineering theory, in use of the concepts of object-oriented abstraction, encapsulation, inheritance and polymorphism, it classifies and integrates the systematic functions, and designs the logical structure of open systems of hierarchical object-oriented, at the same time, on the goal of low coupling, high cohesion, it designs the system’s function modules. In use of the basic principles and heuristic rules, it puts the FC-RTTES system into daily used and designs the system’s physical framework which is object-oriented abstraction. Thus, it designs the public platform of the FC-RTTES which can meet different users’needs, achieve the shares and exchange of the information, integrate and verify algorithms, reasonable, practical, and standardized. Research on the based data processing technology of FC-RTTES. To improve the quality of system based data, analyze and process drift data and redundant data of Taxi GPS, and revise the processed GPS positioning point with digital map. In order to lay a data foundation of removing the link of unconventional OD path for next, analyze the unconventional running status which is probably happens during the taxi running, design a method of identification unconventional parking state and exhumation of the state based on manifestations of data, and mark the corresponding situation of data sequence. Also devise the general solutions of getting GPS taxi travel route of any OD in the road network with the use of vehicle tracking technology.Research on the selection methods for OD valid path of FC-RTTES. For the purpose of making the system get adequate, less redundant reference Information of OD route efficiently, classify any OD travel requisition into2types according to the standard of requested time, one is on basis of O, and the other is on basis of D. For the situation of these2types, finalize the time zone of extraction of real time and historical GPS data. For the purpose of proving the quality and efficiency of selecting OD valid route for the system, classify them into time-discontinued and space-repeated unconventional OD route based on the mechanism of different kinds of unconventional OD route, and then design different methods of identifying and processing based on their own data characteristics. For the purpose of making OD valid route meet the traveling demand of most people, propose the evaluated indicators of validity of these routes:utilization and reliability, and the definition and calculation methods of their own are given, too. Also, finish the design of selection method of K pieces of OD valid routes based on two evaluation rules.Study on the estimation method of the route travel time of FC-RTTES. Concentrating on different kinds of setting off or arriving time requirements of OD travel, this thesis detailedly analyze and ascertain the picking-up zone of the reference database for the time estimation of travel route in different circumstance in order to meet the quality and quantity requirements of the reference database of the time estimation of OD travel route and simultaneously guarantee the high efficiency of the system. By analyzing the basic characteristics of reference database sequence, the estimation model of OD travel route is designed on the basis of OD travel requirements. Focusing on the different circumstances which can refer to historical database in the time repository of OD travel route, methods for applying the database in the repository in the time estimation of travel route are separately designed in order to enhance the system’s efficiency of the time estimation of travel route. Study on the FC-RTTES data’s management method. In order to improve the development and operational efficiency in terms of data organization, it introduces the advanced database technology, on the base of the theory of object-oriented, and on the basics of the former system requirement analysis and the structure framework, we design the flow diagram of the FC-RTTES system, and extract the system and components which are needed in storing the database, it presents a hierarchical data organization method and designs three different types and functions of the data dictionary. It classifies the database, and manages the data in different layers from the point of the applied systems, which forms the data logical models of simple, reasonable and intuitive, as well as the data access mode which occupies the attribute information with dynamic, as a result, it makes the system of data management maintenance, and program development more flexible, convenient and fast.Aiming at the road network in the cities, this thesis studies the method to access the effective travel route of random OD travel requirements and time. To establish the floating car’time estimation system of travel route on the basis of GPS and in allusion to the large amount of GPS floating cars, the thesis brings forward system application database management methods to advance the efficiency of operation and running of the system. It also puts forwards the common effective selecting ways and evaluation standards and designs the time estimation model of travel route. This thesis validates the theory by using the practical data. The result shows that the FC-RTTES system can provide required travel route and time effectively and accurately.This thesis provides timely, accurate and reliable basis of database on travel route for the ATIS travel information service and improve the ATIS service and synthetical efficiency.